title: Long-term evaluation of ANKYLOS® dental implants, part i: 20-year life table analysis of a longitudinal study of more than 12,500 implants.
abstract: OBJECTIVE
  Scientific evidence is limited regarding the long-term (>10 years) outcomes of large enough numbers of implants (>500) to allow for reliable comparison of subgroups. The purpose of this study was to analyze the outcomes of dental implants placed in an active University Clinic setting and followed for up to 20 years.
  
  
  METHODS
  Data documenting the implant placement, prosthetic reconstruction, and annual follow-up of patients treated at Frankfurt University were extracted from a Structured Query Language database and patients' written records and evaluated statistically.
  
  
  RESULTS
  Between April of 1991 and May of 2011, 12,737 ANKYLOS® (DENTSPLY Implants Manufacturing GmbH, Mannheim, Germany) implants were placed in 4,206 patients for a variety of clinical indications. The Kaplan-Meier cumulative survival rate (CSR) was 93.3% after 204 months. Most of the failures (198/1.6%) occurred during the first year after implant placement and before prosthesis delivery. A significantly higher (p < .001) number of implants placed in the mandible and in hard quality bone failed than those placed in the maxilla or in weak and normal quality bone. Female patients had significantly higher CSRs (93.7% 204 months) than male patients (92.8% 204 months/p = .029). The implants showed low rates of peri-implant bone loss after 204 months (horizontal: ≤1 mm: 85.7%, vertical: ≤1 mm: 85.2%).
  
  
  CONCLUSIONS
  ANKYLOS dental implants followed for up to 20 years have high CSRs and low rates of peri-implant bone loss.
authors.affiliation: Department of Oral Surgery and Implantology, School of Dentistry (Carolinum), Johann Wolfgang Goethe-University Frankfurt am Main, Frankfurt am Main, Germany.
authors.forename: Mischa
authors.initials: M
authors.lastname: Krebs
authors.forename: Kai
authors.initials: K
authors.lastname: Schmenger
authors.forename: Konrad
authors.initials: K
authors.lastname: Neumann
authors.forename: Paul
authors.initials: P
authors.lastname: Weigl
authors.forename: Walter
authors.initials: W
authors.lastname: Moser
authors.forename: Georg-Hubertus
authors.initials: GH
authors.lastname: Nentwig
mesh_terms: D000368:Aged; D003758:Dental Implantation, Endosseous; D015921:Dental Implants; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D005260:Female; D005858:Germany; D006801:Humans; D015993:Life Tables; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D016348:Osseointegration; D017063:Outcome Assessment, Health Care; D011183:Postoperative Complications; D012307:Risk Factors; D016019:Survival Analysis
chemical_list: D015921:Dental Implants
keywords: clinical research; clinical study; crestal bone loss; implant; implant survival; long-term survival; marginal bone loss; survival rate